... pellet material with the purity of 99.996-99.999%, density of 3.0-3.6g/cm.Main applications ... ball material with the purity of 99.996-99.999%, density of 2.5-3.5g/cm.Main uses ... :1.Filling2.Heat insulation layerSapphire crystal LED 99.999%Sapphire crystal is processed with high purity alumina powder ... crystal to get sapphire crackle with the purity of 99.999%, density of 3.95g/cm. Which is the ...